This invention relates to the use of ultrasonic measurement techniques, and more particularly, to the measurement of the thickness of a pipe or other conduit which is covered with a layer of coating to determine the remaining useful life of the pipe or conduit.
In a variety of industrial settings, pipes are used to conduit liquids and gases from one location to another. Many times these are corrosive fluids which, over time, will cause the pipes to have to be replaced. At the same time, it is not unusual for the pipes to painted with a coating material to protect the outside of the pipe from the weather, or from other materials in the atmosphere which would react with the pipe if the pipe comes into contact with the materials. As part of the maintenance required on a fluid flow system, it is desirable from time-to-time to measure the thickness of a pipe. If the measured thickness is less than some minimum value, then the pipe should be replaced. With coated pipes, however, there is a problem in that the layer of coating material effects the measured thickness value, causing errors in the value. If the error is such as to indicate that the conduit is thinner than it actually is, then the pipe is replaced before the actual end of its useful life, thereby unnecessarily increasing maintenance costs. If the error indicates the pipe is actually thicker than it actually is, then the pipe may fail before it can be replaced, not only needlessly shutting down the facility, but also incurring expensive cleanup costs.
Ultrasonic thickness measuring techniques are known. However, heretofore, it has not been possible to accurately measure pipe thickness when the pipe has been painted with a layer of a coating material. In accordance with the present invention, that is now possible.